Separation of benzene/cyclohexane mixture using semifluorinated aromatic poly(ether amide) membranes with and without cardo unit in the main chain

This paper describes the pervaporation study of benzene (Bz)/cyclohexane (Chx) (50/50 wt%) mixture through four structurally different semifluorinated aromatic poly(ether amide) (PEA) membranes (PEA I, PEA II, PEA III and PEA IV). The effects of variation of molecular structure on pervaporation performances towards Bz/Chx (50/50 wt%) mixture at three different temperatures (50, 60 and 70 °C) were studied and the results indicated that the membranes were benzene-selective in nature. The poly(ether amide), PEA IV containing cardo phenolphthalein anilide unit in the main chain showed the highest permselectivity value of 5.9 for a Bz/Chx mixture and the poly(ether amide), PEA III containing cardo fluorene moiety in the main chain showed highest permeation rate of 31.42 kg μm/m2 h in the series. The activation energies for pervaporation of Bz, Chx and Bz/Chx mixtures through the PEA membranes have been calculated from the Arrhenius equation.