Influence of filler microstructure on propylene/propane separation in calixarene-based mixed matrix membranes

The pure organic nature and solubility of calixarenes in organic solvents position them as prospective fillers for mixed matrix membranes (MMMs). This investigation incorporated two calixarene materials, C-propylpyrogallol[4]arene (PgC 3 ) and sulfonato-calix[6]arene (SCA6), into a 6FDA-TMPDA matrix to fabricate MMMs targeting C 3 H 6 /C 3 H 8 separation. The separation performance of two calixarenes based MMMs were investigated at various filler loadings. SCA6 was found to be a more suitable filler for 6FDA-TMPDA as its abundant -OH and -HSO 3 functional groups, which strengthened filler-matrix interfacial compatibility. The membrane containing 1 wt% SCA6 in 6FDA-TMPDA exhibited optimal performance, attaining the C 3 H 6 permeability of 69.3 Barrer and an ideal selectivity of 17.3, surpassing the polymeric upper limit. The PgC 3 /6FDA-TMPDA MMMs also displayed a marked selectivity enhancement from 7.1 to 18.9. Both 1 wt% SCA6/6FDA-TMPDA and 5 wt% PgC 3 /6FDA-TMPDA membranes demonstrated long-term stability up to 20 days. The excellent separation performance and operational stability of these MMMs offer a promising alternative for efficient C 3 H 6 /C 3 H 8 separation. Calixarene mixed matrix membranes achieving outstanding C 3 H 6 /C 3 H 8 separation performance beyond polymeric limits together with long-term stability.