Adsorptive desulfurization on a heteroatoms Y zeolite prepared by secondary synthesis

Gallium atoms have been introduced into the framework of Y zeolite by treating the zeolite with an aqueous solution of ammonium hexafluoro gallate. Desulfurization of various model fuels containing about 500 mu g/g sulfur has been studied over the synthesized Y zeolite ([Ga]AlY). The sulfur adsorption capacity is 7.0, 17.4, 14.5, 16.9, 6.9 and 5.8 mg(S)/g adsorbent for thiophene, tetrahydrothiophene (THT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), dibenzophiophene (DBT), benzothiophene (BT) and 4-methyldibenzothiophene (4-MDBT), respectively. The charges on the S atom in thiophene, THT, 4,6-DMDBT, DBT, BT and 4-MDBT, calculated using the density functional theory (DFT), are -0.159, -0.298, -0.214, -0.211, -0.193 and -0.188, respectively, implying that the S-M bond between the adsorption sites and thiophene is much weaker than that between the adsorption sites and THT, 4,6-DMDBT or DBT. The sulfur removal of FCC gasoline on [Ga]AlY is 68%.