The Adsorptive Removal of Thiophene from Benzene over ZSM-5 Zeolite

ZSM-5 zeolites with different Si/Al ratio (25, 38, 50) were selected for the research of adsorptive removing thiophene from benzene and the desulfurization behavior of H-ZSM-5(25) sorbent acid-modified and ion-exchanged was studied. The experimental results show that the sorbent H-ZSM-5(25) from acid-modified ZSM-5 zeolite with a Si/Al ratio of 25 is the best sorbent with the largest amount of Brönsted acidic sites, which plays an important role in the adsorption of thiophene. The results of the sorbents from H-ZSM-5(25) ion-exchanged with Ag+, Ni2+, Ce3+, and La3+ show that the desulfurization efficiency is increased for all ion-exchanged zeolites, because thiophene can be adsorbed via π-complexation over Ag-ZSM-5(25) and Ni-ZSM-5(25) zeolites, while through the S–M bond on Ce-ZSM-5(25) and La-ZSM-5(25) zeolites. Benzene can bring the effect of competitive adsorption with thiophene via π-complexation, so the efficiency of Ce-ZSM-5(25) and La-ZSM-5(25) removing thiophene from benzene by the selective S–M bond is better than that of Ag-ZSM-5(25) and Ni-ZSM-5(25), which can respectively reach to 92.7 and 93.9%.