PCTFE microporous membrane with high corrosion-resistance and ultra-fast oil/water separation performances

Abstract

Membrane separation technology is a promising choice for treating oily water from industrial and domestic sewage. The elaborate design of pore structure can realize a good trade-off between separation flux and efficiency, thus taking the full advantages of membrane separation. Herein, polychlorotrifluoroethylene (PCTFE) microporous membrane with tunable pore structure was fabricated via a sacrificial template method. Fluoroelastomer (FR), serving as sacrificial template, was incorporated into PCTFE via a solvent-assisted method, forming PCTFE/FR blending films. After removing FR via solvent-dissolving, porous PCTFE membrane was obtained. More important, the gradual increment of FR loading made the morphology of PCTFE/FR blending films realize the transformation from “sea-island” to bicontinuous structure, thus endowing the membranes with tunable pore structure, surface wettability, as well as mechanical properties. Among the candidates, 50FR membranes possessed good flexibility, twist-resistance, as well as excellent creep-resistance and can efficiently separate oil from various water/oil mixtures. The oil (dichloromethane) permeability, separation efficiency, and filtrated oil purity were high up ∼10000 L/(m²⋅h), ∼99 %, and ∼99.92 wt%, respectively. Additionally, although undergoing 25 separation cycles or being immersed into various highly-corrosive liquid (including 1 M HCl, 1 M NaOH, DMF, ethanediamine, and concentrated HNO₃) for 7 days, the properties of the membrane changed little. These features suggested a great potential for preparing PCTFE membranes used for oil/water separation in various harsh environment.