(330i) Polydimethylsiloxane/polyvinylidene Fluoride Composite Membrane for Separation of N-Butane /N2 Mixture

Composite membranes made by coating polydimethylsiloxane (PDMS) on polyvinylidene fluoride (PVDF) microporous membrane have been used for separating volatile organic compounds (VOCs) from permanent gases in many commercial applications. In this research, the permeability of n-C4H10 and N2 in the PDMS coated PVDF composite membranes were measured. It is shown that the permeability and selectivity strongly depended on the temperature and feed pressure. The results shows that the permeability of n-butane decreases as the operating temperature increases, but nitrogen follows the opposite trend in the operating temperature range 283K-343K and the pressure range 0.01MPa-0.15MPa. The relationship between the permeability of both n-butane and N2 and temperature agree with the Arrhenius equation. The permeability of n-butane increases as feed pressure increases, especially at low temperature, while the permeability of nitrogen is not sensitive to feed pressure. At the feed pressure 0.1MPa and operating temperature 318K, the permeability of n-butane is 15000 barrier, and the permeability of N2 is 200 barrier. The ideal separation factor is 75. It is concluded that the PDMS/PVDF composite membrane we made can be used to separate n-butane/N2 mixture.