Mixed matrix membranes composed of WS2 nanosheets and fluorinated poly(2,6-dimethyl-1,4-phenylene oxide) via Suzuki reaction for improved CO2 separation

A method of introducing trifluoromethyl group (-CF 3 ) to the polymer backbone by Suzuki reaction was developed to prepare fluorinated polymers for gas separation. The CO 2 permeability increased 119% after the -CF 3 group was substituted. Tungsten disulfide (WS 2 ), a graphene-like two-dimensional material, was used for first time as an inorganic filler to prepare composite MMMs to separate CO 2 , N 2 and CH 4 . The introduction of WS 2 nanosheets increases more transport channels for gas molecules, which lead to the permeability and selectivity of MMMs obviously improved in comparison with the pristine FPPO membrane. The CO 2 /N 2 selectivity and CO 2 /CH 4 selectivity of 10 wt% WS 2 -FPPO MMMs reached a maximum about 29.6 and 39.4, respectively, with a CO 2 permeability of 472 Barrer at 10 psig and 291 K. The best performance of MMMs for CO 2 /N 2 and CO 2 /CH 4 surpasses the Robeson's upper bound line. The MMMs showed strong stability in long-term observation. The results indicated a new direction for CO 2 separation by introducing -CF 3 group to polymer and using 2D WS 2 nanosheets as nanofiller.