Adsorption characteristics of tetrahydrothiophene and tert-butylmercaptan on Na-Y and Ag-Y zeolites

Removal of sulfur compounds is markedly important in the fuel processing for fuel cell applications because sulfur poisons fuel processing catalysts and fuel cell electrodes, which result in significant decrease in their catalytic and electrochemical activities. Adsorptive removal of sulfur species from fuels has been widely explored in recent years because it is easily practicable compared to the HDS which require high operation temperatures and pressures. In addition, effluent sulfur concentrations in parts per billion levels could be achieved using adequately selected or designed adsorbents. Among various adsorbents for the applications, Ag-Y zeolites have been known to offer high breakthrough and saturation sulfur adsorption capacities. The effect of silver in the breakthrough and saturation uptake of tetrahydrothiophene (THT) and tert-butylmercaptan (TBM) on NaAg-Y was studied at various Ag⁺ exchange levels. Silver gave a little effect on breakthrough THT uptake, but enhanced TBM uptake significantly. These were explained by the adsorption strength caused by Na and Ag cations. This is an abstract of a paper presented at the 231st ACS National Meeting (Atlanta, GA 3/26-30/2006).