Removal of tetrahydrothiophene by an adsorption method

Adsorptive removal of thiophene and alkyl-thiophene from liquid fuels can be effectively carried using the metal ion-exchanged Y-zeolites. The adsorptive removal of tetrahydrothiophene (THT) at ambient temperatures and pressure was studied using various adsorbents (BEA, mordenite, Na-Y, and Ag-Y). The Na-Y zeolite showed the highest adsorption capacity, followed by BEA and mordenite. Considering the molecular size of THT (5.3 × 3.5 Å) and the pore dimensions of the adsorbents, it appeared that adsorbents with pore dimensions larger than the molecular size of THT offer high adsorption capacities. In the case of Na-Y zeolite, the fraction of large sorption sites was presumably high, and this resulted in the high sorption capacity for THT. Conversely, a significant fraction of the sorption sites in mordenite is smaller than the THT molecules, resulting in the low THT adsorption capacity. The THT adsorption capacity of Ag-Y did not show a monotonous correlation with Ag ion-exchange level. Another crucial factor for a high sorption capacity would be crystallinity of the adsorbents. This is an abstract of a paper presented at the 2005 AIChE Annual Meeting and Fall Showcase (Cincinnati, OH 10/30/2005-11/4/2005).