Removing thiophenes from n-octane using PDMS-AgY zeolite mixed matrix membranes

PDMS-AgY zeolite mixed matrix membranes were prepared for separation of thiopenes from mixture of n-octane, thiophene and 2-methylthiophene. Experimental results show that AgY zeolite incorporation in PDMS membranes leads to a significant increase in total flux. This can mainly be attributed to the Knudsen diffusion of the feed species in the macro- and meso-pores existing in AgY zeolite. Effect of AgY filling on the selectivity is a trade-off between the interaction of AgY zeolite particles and thiophenes and the Knudsen diffusion occurring in the zeolite pores. Only a slight decrease in enrichment factor for both the thiophenes could be found in the mixed matrix membranes. Moreover, the difference between enrichment factors of non-filled and filled membranes become unapparent when the temperature increases, implying that a kinetic barrier in the sorption and desorption process on the surface or within the pores of AgY zeolites might exist. Most experimental points of AgY-filled PDMS membranes locate above the upper bound curve of pure PDMS membranes for separation of n-octane/thiophenes, indicating that higher permeability was gained with little expense of selectivity using PDMS-AgY zeolite mixed matrix membranes. (C) 2007 Elsevier B.V. All rights reserved.