Ionic liquid copolymerized polyurethane membranes for pervaporation separation of benzene/cyclohexane mixtures

Benzene and cyclohexane are both important raw materials in polymer chemical industry. However, they are hard to be separated via the traditional distilling methods. In this work, ionic liquid copolymerized waterborne polyurethane (IL-co-PU) membranes were proposed for the pervaporation separation of benzene/cyclohexane mixtures. The results, including swelling rate, diffusion coefficients , partial flux, permeance and selectivity, showed that the IL-co-PU membranes could preferentially absorb and transfer benzene molecules rather than cyclohexane . The ILs might have functioned as facilitated transporter in the membranes. The permeation flux and separation factor of the IL-co-PU membranes increased simultaneously with the increase of IL contents. That is, these membranes had no trade-off between permeability and selectivity, which most of the polymer membranes suffered. With consideration of the good performance and easy handling property of the IL-co-PU membranes, they are of great potential in pervaporation separation of benzene/cyclohexane mixtures.