Selective adsorption of dibenzothiophene by functionalized metal organic framework sorbents

The adsorption of organosulfur compounds directly from liquid fuels has potential advantages over hydrodesulfurization processes including higher efficiencies and lower costs. A series of sorbents was prepared by decomposing Mo(CO)6 onto MOF-5, and evaluated for the selective adsorption of dibenzothiophene from solutions containing i-octane, naphthalene and/or benzene. The resulting materials had Mo loadings up to 20 wt%, surface areas in excess of 1800 m2/g and pore size distributions that were very similar to those for the parent MOF-5. Other than features for MOF-5, there was no evidence of crystalline domains larger than 50 nm in the X-ray diffraction patterns, although, Mo(CO)6 typically decomposes into Mo carbide and/or oxycarbide species under the conditions employed. These materials possessed strong affinities for the adsorption of dibenzothiophene in the absence and presence of the types of aromatic compounds typically found in transportation fuels. Sulfur uptakes at breakthrough approached 0.5 mmolS/g which corresponded to surface coverages of ∼4%. With further development, these materials could be used to remove sulfur from gasoline, diesel and military logistics fuels.

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► Synthesized MOF-5 supported adsorbents while preserving high surface areas.
► Adsorbents possessed high capacities and selectivities for organosulfur compounds.
► Could be developed for military and commercial desulfurization applications.