Liquid-liquid interface induced high-flux PEBA pervaporation membrane for ethanol recovery

Abstract

Bioethanol has achieved increasing attention in alleviating energy crisis and environmental issues. Pervaporation could be a promising technology to separate ethanol from fermentation. Traditionally, the liquid polymetric solution was compounded on solid porous supports to form composite membranes. Through this liquid-solid interface, it is challenging to precisely control the structure and achieve high pervaporation performance. In this work, we aimed to overcome some of these limitations and designed a polyether block amide (PEBA) pervaporation membrane by dropping the membrane solution on a water surface. While the membrane solution spreading, solvent-water exchange and solvent evaporation occurred. Thereafter the polymer precipitation was induced in the solvent-water interface. The defect-free and uniform selective layer with a thickness of 3.9 μm was achieved by optimizing the ratio of solvent, and the temperature of the water. The PEBA layer was deposited onto porous polytetrafluoroethylene (PTFE) substrate for recovering ethanol from water by pervaporation. The membrane represented a total flux and separation factor of 3.9 kg m−2 h−1 and 4.9, which was maintained stable for 100 h. The interface-induced membrane demonstrated high separation performance and membrane stability.