A novel ternary mixed matrix membrane containing glycerol-modified poly(ether-block-amide) (Pebax 1657)/copper nanoparticles for CO2 separation

Abstract

A novel high-performance mixed matrix membrane (MMM) with a low amount (< 2 wt%) of filler loading was fabricated in which the synthesized copper nanoparticles (Cu) incorporated into a glycerol-modified poly(ether-block-amide) (Pebax 1657, Pe). Glycerol (Gl) as an affordable low molecular weight additive provides a good CO2 affinity. On the other hand, the presence of Cu nanoparticles improves CO2 permeability through a facilitated transport mechanism, with destruction of the well-packed polymer chain structure and breaking the hydrogen-bond between Gl and Pe chains. First, pure Pe membrane was modified by adding different amounts of Gl (0–25 wt%). The optimum membrane (Pe/Gl (15 wt%)) was determined by measuring the CO2/N2 gas permeation properties. It was shown that the selectivity was dramatically increased (~ 172%) from 81.9 (for pure Pe) to 222.7 (for Pe/Gl (15 wt%)), while a fairly significant decrease (over 23%) in CO2 permeability (from 65.71 for pure Pe to 50.42 for Pe/Gl (15 wt%)) was obtained at 25 °C and 10 bar. Second, the synthesized Cu nanoparticles were embedded (0–2 wt%) into the Pe/Gl (15 wt%) matrix to fabricate the Pe/Gl/Cu MMMs. The results revealed that Pe/Gl (15 wt%)/Cu (1.5 wt%) membrane has a higher permeability (63.6 Barrer, 25 °C and 10 bar), and to some extent a lower selectivity (200) in comparison with the Pe/Gl (15 wt%) membrane. However, it presents an approximately similar permeability but a distinct increase (144%) in selectivity compared to the pure Pe. Accordingly, a series of high-performance Pe/Gl/Cu MMMs were fabricated which surpassed the Robeson's upper limit and can be as the promising membranes for CO2 separation.