Green solvents for the fabrication of polymer inclusion membranes (PIMs)

Chemical separation based on polymer inclusion membranes (PIMs) is a "Green Chemistry" alternative to solvent extraction by drastically reducing the use of toxic and volatile solvents which are used predominantly in PIM fabrication. This paper thus assesses the suitability of non-hazardous and renewably sourced "green" solvents (i.e., acetone, ethyl acetate, 2-methyltetrahydrofuran, and dihydrolevoglucosenone (Cyrene (TM))) for the fabrication of PIMs composed of the most commonly used polymers (i.e., poly(vinyl chloride) (PVC), cellulose triacetate and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)) and extractants (i.e., di-(2-ethylhexyl) phosphoric acid and Aliquat 336). It is demonstrated that PVC- and PVDF-HFP-based PIMs fabricated with 2-methyltetrahydrofuran and ethyl acetate, respectively, exhibit extraction performance and stability similar to those of their counterparts fabricated with the conventional solvent tetrahydrofuran, even though their surface morphologies were slightly different. This result indicates that "green" solvents are a viable alternative to conventional "non-green" solvents used in the fabrication of PVC- and PVDF-HFP-based PIMs.