Extra-high-performance low-level filler-loaded mixed-matrix membranes (MMMs) were fabricated by embedding a flexible cyclooligomer, calix[4]arene (CA), as a macrocyclic porous filler in two blends of a commercial polyether block amide polymer, Pebax MH 1657. Two kinds of liquid phases, PEG550 (PEG) and [OMIM][PF6] (IL), were separately introduced into the Pebax MH 1657 matrix to prepare blended membranes for enhancing the CO2 permeability and comparing their performance. Afterward, CA as the third generation of supramolecular hosts with high inherent affinity to CO2 was synthesized and incorporated in the polymer blends to fabricate high-performance MMMs. The organic nature, the high compatibility of other applied additives with Pebax MH 1657 polymer, and the tiny size of CA particles were responsible for the desirable particle distribution in ternary MMMs. In the case of the Pebax/PEG550 (30 wt%)/CA (0.5 wt%) MMM, the results revealed the CO2 permeability to be about 632.60 Barrer, with CO2/CH4 and CO2/N2 selectivities about 59.83 and 139.88, respectively. For Pebax/IL (6.5 wt%)/CA (0.5 wt %), the CO2 permeability was about 263.82 Barrer, with CO2/CH4 and CO2/N2 selectivities about 64.39 and 152.45, respectively. Therefore, the fabricated ternary MMMs present a promising outlook for CO2 separation, which surpasses the Robeson upper limits.
