Pervaporation separation of n-octane/thiophene mixtures using polydimethylsiloxane/ceramic composite membranes

Crosslinked polydimethylsiloxane (PDMS)/ceramic composite membranes were prepared and employed for desulfurization of model gasoline composed of n-octane and thiophene. The structural morphology and thermal stability of the composite membranes were characterized by scanning electron microscope (SEM) and thermogravimetric analysis (TGA). The pervaporation performances of the membranes under various crosslinking agent amounts, feed sulfur content, feed temperature, permeate pressure and feed flow rate were investigated. Experimental results indicated that 20% of the crosslinking agent amount was more preferable. Increase of sulfur content in feed resulted in a higher total flux but a lower sulfur enrichment factor. By increasing the feed temperature, the total flux increased while sulfur enrichment factor decreased. Low permeate pressure and high feed flow rate were beneficial to improve total flux and sulfur enrichment factor. At 303.15K, the composite membrane exhibited high performance with the total flux of 5.37kg m^-2 h^-1 and the corresponding sulfur enrichment factor of 4.22 for 400μg g^-1 sulfur in feed under 210Pa. Our results showed that the PDMS/ceramic composite membrane was a potential candidate to be used for sulfur removal from the gasoline.