Preparation, characterization of P(VDF-HFP)/[bmim]BF4 ionic liquids hybrid membranes and their pervaporation performance for ethyl acetate recovery from water

Poly(vinylidene-fluoride-hexafluoropropene)/1-butyl-3-methyl-imidazolium-tetrafluoroborate (P(VDF-HFP)/[bmim]BF4) hybrid membranes were prepared by solvent evaporation methods using P(VDF-HFP) as membrane matrix and acetone-[bmim]BF4 mixtures as solvent. The surface and cross-sectional morphology of the membranes were characterized by using Scanning Electro Micrograph (SEM), and swelling behavior and pervaporation performance were investigated for separating ethyl acetate/water. The SEM results showed that [bmim]BF4 was successfully embedded in the P(VDF-HFP) matrix. Inclusion of [bmim]BF4 in the P(VDF-HFP) matrix enhanced diffusion coefficient of EtAc. As [bmim]BF4 content increased from 0 to 5 wt.%, the total permeation flux of the membrane increased from 433.21 to 655.85 g.m− 2.h− 1 and the separation factor increased from 75.75 to 143.88 for 4 wt.% EtAc/water at 45 °C. The TGA and stability experiments further demonstrated that hybrid membranes had good thermal stability during separation process.

► Polymer/[bmim]BF4 hybrid membrane was prepared using [bmim]BF4/acetone mixed solvent.
► [Bmim]BF4 were successfully embedded in the P(VDF-HFP) membrane.
► Solid membrane inclusion liquid ionic liquids have higher transport coefficient.
► Embedding of [bmim]BF4 in P(VDF-HFP) can enhance its separation performance.
► P(VDF-HFP)/[bmim]BF4 hybrid membranes showed good thermal stability.