Deep desulfurization by selective adsorption on a heteroatoms 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 were studied over the synthesized Y zeolite ([Ga]AlY) with a liquid hourly space velocity of 7.2 h(-1) at ambient conditions. The sulfur adsorption capacity was 7.0, 14.5, and 17.4 mg(S)/g adsorbent for thiophene, 4,6-dimethyldibenzothiophene (4,6-DMDBT), and tetrahydrothiophene (THT), respectively. The charges on S atom in thiophene, 4,6-DMDBT and THT, calculated by using density functional theory (DFT), are -0.159, -0.214 and -0.298, respectively, implying that the S-M bond between the adsorption sites and thiophene is much weaker than that between the adsorption sites and THT or 4,6-DMDBT. (c) 2007 Elsevier B.V. All rights reserved.