Selective adsorption of thiophene and 1-benzothiophene on metal-ion-exchanged zeolites in organic medium

Adsorption of the organic sulfur compounds thiophene (TP) and 1-benzothiophene (1-BTP) in an organic model solution of hydrodesulfurizated gasoline (heptane with 1 wt% toluene and 0.156 mM (5 ppmw as sulfur) TP or 1-BTP) was studied by a batch method at 80 °C using metal-ion-exchanged Y-zeolites. Although NaY-zeolite or its acid-treated material rarely adsorbed the organic sulfur compounds, NaY-zeolites exchanged with Ag +, Cu 2+, and Ce 3+ ions and NH 4Y-zeolites exchanged with Ce 3+ ions showed markedly high adsorptive capacities for TP and 1-BTP. The sulfur uptake increased in the order CuY-zeolite(Na) < AgY-zeolite(Na) < CeY-zeolite(Na) for both the organic sulfur compounds. The adsorption isotherms for TP and 1-BTP followed the Langmuir's relationship and the saturation capacities by CeY-zeolite(Na) were calculated as 0.022 and 0.033 mmol / g , respectively. The mole ratios of TP/Ce and 1-BTP/Ce were 0.031 and 0.047, respectively. CeY-zeolite(NH 4) which was prepared from NH 4Y-zeolite showed less uptake of TP and 1-BTP than CeY-zeolite(Na), probably due to its lower cerium content.