Synthesis of fluorine-containing conjugated microporous polymers and their application for highly efficient oil/water separation

Two fluorine-containing conjugated microporous polymers (CMP-F) have been synthesized by Sonogashira coupling polymerization. The CMP-F powders show high yield, high porosity, high thermal stability, and high water contact angles up to 128°. Due to its high hydrophobicity, the CMP-F polymers are used as fillers for fabricating oil/water separation mixed-matrix membranes (MMMs). CMP-F/PI MMMs were prepared by the electrospinning method with polyimide as the matrix for the first time. The CMP-F/PI MMMs exhibited a high separation efficiency of at least 99.5% for all the tested oils, such as toluene, ethyl acetate, hexane, CCl4 and gasoline, against water. The maximum flux of hexane reached to 13500 L/(m2∙h), and the stability of the separation efficiency was maintained at approximately 99.5% for fifteen cycles. Surprisingly, the MMMs displayed highly-efficient diesel/water separation properties with separation efficiencies of up to 99.7%, although it is well known that it is difficult to efficiently separate diesel from water owing to its complex composition and high viscosity. In addition, a water-in-toluene emulsion could be separated by CMP-F/PI MMMs with a separation efficiency of up to 99.1%. CMP-F/PI MMMs have high potential for application in emulsion separation.