Capillary supported ultrathin homogeneous silicalite-poly(dimethylsiloxane) nanocomposite membrane for bio-butanol recovery

An ultrathin (300 nm) homogeneous silicalite-poly(dimethylsiloxane) (PDMS) nanocomposite membrane was fabricated on capillary support by a “Packing–filling” method. Firstly, silicalite-1 nano-crystals were deposited onto a porous alumina capillary support using dip-coating technique (packing); secondly, the interspaces among the nano-crystals were filled with PDMS phase (filling). No voids between nano-crystals and PDMS phase were observed by scanning electron microscopy (SEM), suggesting good zeolite–polymer adhesion. The membrane possesses very high flux (5.0–11.2 kg m−2 h−1) and good separation factor (25.0–41.6) for the pervaporative recovery of iso-butanol from aqueous solution (0.2–3 wt.%) at 80 °C. Such properties offer great potential towards applications in fermentation–pervaporation coupled processes. The effects of feed temperature and concentration on the pervaporation performance of this nanocomposite membrane were investigated.