Mixed matrix membranes comprising a polymer of intrinsic microporosity loaded with surface-modified non-porous pearl-necklace nanoparticles

Abstract

The fabrication of mixed matrix membranes (MMMs), with a view to using them for gas separation applications, such as the capturing and separating carbon dioxide, oxygen, or nitrogen from air, and natural gas separation, has been thoroughly explored. Here we report on MMMs containing surface-modified non-porous pearl-necklace nanoparticles (P-NP), which were synthesized by connecting together approximately six spherical nanoparticles. The gas permeability of MMMs containing P-NPs increased with increasing P-NP concentration, and the increase was associated with the formation of micro- and meso-pores, which were confirmed using the nitrogen-adsorption/desorption and 129Xe NMR measurements. The permeabilities of an MMM containing 50 wt% P-NP for CO2, O2, N2, and CH4 were 15200, 2850, 916, and 1340 Barrer, respectively. This MMM also had a CO2/N2 selectivity of 16.6, CO2/CH4 selectivity of 11.4 and O2/N2 selectivity of 3.1. The gas permeation data of the resulting MMM was above the 2008 Robeson upper bound line for CO2/N2, CO2/CH4, and O2/N2 gas pairs. This strategy, using anisotropic nanoparticles with a large gas permeable space, has the potential to be applied to the fabrication of MMMs for gas separation.