The pervaporative membrane with vertically aligned carbon nanotube nanochannel for enhancing butanol recovery

Abstract

Vertically aligned (VA) and open-ended carbon nanotube (CNT) arrays filled polydimethylsiloxane (PDMS) composite membrane was fabricated, characterized, and evaluated for pervaporative recovery of butanol from acetone-butanol-ethanol (ABE) fermentation broth. The VA CNT (open-ended)/PDMS membrane displayed various advantages over homogeneous PDMS membrane, since the VA CNT (open-ended)/PDMS membrane demonstrated a simultaneous improved butanol flux and separation factor, which was the result of higher butanol solubility and diffusivity of this membrane. Both butanol flux and separation factor showed a sharp enhancement with increasing feed temperature (30–80 °C), and with increasing feed butanol concentration (5–25 g/L). The maximum total flux and butanol separation factor of the VA CNT (open-ended)/PDMS membrane reached 1093.7 g/m2 h and 37.6 at 80 °C, respectively. The composite membrane showed a stable performance for long-time continuous operation with fermentation broth for biobutanol production. Overall, the VA CNT (open-ended)/PDMS membrane showed higher butanol flux and selectivity than homogeneous PDMS membrane, and has great potentials for butanol separation from ABE fermentation.