Constructing high-efficiency transport pathways via incorporating DP-POSS into PEG membranes for pervaporative desulfurization

Constructing high-efficiency transport pathways in polymeric membranes by incorporation of porous fillers has become one of the most prospective methods to break the trade-off effect between membrane selectivity and permeability. Herein, nanoscale dodecyl phenyl polyhedral oligomeric silsesquioxane (DP-POSS) were incorporated into polyethylene glycol (PEG) polymer to fabricate DP/PEG mixed matrix membranes (MMMs) for pervaporation desulfurization. The large internal diameter (0.68 nm) of cage-like DP-POSS particles facilitated the sorption and diffusion of thiophene molecules, and the phenyl groups of DP-POSS might also enhance the preferential sorption of thiophene due to p-π conjugation. The decrease of PEG crystallinity and enhancement of polymer chain mobility contributed to the larger free volume of MMMs, which was also favorable to the mass transfer for small molecules. Accordingly, the resultant DP/PEG-5 MMMs exhibited separation performance with an optimum enrichment factor of 28.9 and permeation flux of 355.3 g/(m2h), achieving 86.5% and 65.0% higher than the pristine membrane. This study might extend strategies to design high-performance MMMs by immobilization nanoscale POSS into polymers for desulfurization.