2.3. Pervaporation membrane and module
The ultra-thin film silicalite-1 filled PDMS/PAN composite membrane was made in our laboratory. The membrane module with an effective membrane area of 0.0072 m2 was connected with two parallel cold traps, followed by a vacuum pump. The module could be heated by a heater band and a peristaltic pump was used for recirculation of liquid mixture. When coupled with fermentation, the PV membrane was sterilized by circulating 30% ethanol aqueous solution for 12 h, followed by washing with 500 mL of sterilized distilled water. The pressure at the permeate side was maintained at around 280 Pa throughout the experiment. The permeate was sampled from the cold traps in a liquid nitrogen bath at intervals to determine the permeation rate and permeate composition