Liquid–liquid interface induced PDMS‐PTFE composite membrane for ethanol perm‐selective pervaporation

Abstract

Pervaporation has great potential in the separation of many significant mixtures.However, excessive penetration of separation layer into the substrate pores enhances the transport resistance of solvent molecules, which impedes the development of pervaporation membrane. In this study, a facile floating-on-water (FOW) method was used to prepare poly(dimethylsiloxane) (PDMS)/polytetrafluoroethylene (PTFE) composite membranes. The formation of separation layer and preparation of composite membrane were step-by-step completed through this liquid-liquid interface induced method. The PDMS layer thickness could be precisely regulated from 0.5 to 8 μm. Moreover, the pore penetration could be controlled by optimizing precrosslinking density, crosslinking time on water and polymer solution volume. The obtained PDMS/PTFE composite membrane exhibited a high flux of 2016 gÁm À2 Áh À1 with the separation factor of 12 when separating ethanol from a 5 wt% ethanol/ water mixture. The performance of the membrane could be stable for over 200 h, exhibiting great potential in ethanol perm-selective pervaporation.

The Production of Bioethanol from Lignocellulosic Biomass: Pretreatment Methods, Fermentation, and Downstream Processing

“…Li et al synthesized a composite membrane consisting of a PDMS ultra-thin selective layer (thickness from 0.5 to 8 µm) on porous polytetrafluoroethylene (PTFE) support. The membrane exhibits a high flux of 2016 g m −2 h −1 with a separation factor of 12 for the separation of ethanol from a 5 wt% solution with stable operation over 200 h [188]. Furthermore, several other polymers have been proposed for the recovery of alcohol diluted aqueous solutions by pervaporation, including homopolymers and copolymers of siloxane (e.g., polymethylethoxysiloxane (PMES), polymethylphenylsiloxane (PMPS), polyphenylmethylsiloxane (PPMS), polydimethylsiloxane-imide (PDSI), polysiloxaneimides (PSI), polyoctylmethylsiloxane (POMS), etc.…”

Fabrication of highly permeable PDMS@ZIF‐8/PVDF hollow fiber composite membrane in module for ethanol‐water separation

“…The preparation of effective separation membranes is the key to achieve superior separation performance of membrane modules. To this end, hydrophobic polymers with high stability and low cost, such as polydimethylsiloxane (PDMS) and poly(ether block amide) (PEBA), have been coated on hollow fiber substrates to prepare ethanol‐selective PV membrane modules 16 . However, these membrane modules are usually constrained by the trade‐off between permeability and selectivity, necessitating further exploration for better performance.…”