Confinement of microporous MOF-74(Ni) within mesoporous γ-Al2O3 beads for excellent ultra-deep and selective adsorptive desulfurization performance

Abstract

The microporous MOF-74(Ni) was impregnated on mesoporous γ-Al2O3 beads leading to successful formation of a hierarchical multiporous composite MOF-74(Ni)@γ-Al2O3 containing 10 wt% MOF-74(Ni) via solvothermal method. The confinement effect introduced by the channels of γ-Al2O3 beads resulted in ultrathin continuous films of MOF-74(Ni) which has significantly enhanced the surface area and surface utilization rate by ca. 16%. The composite showed excellent adsorptive desulfurization in the order of dibenzothiophene (DBT) ≈ benzothiophene (BT) > 4,6-dimethyldibenzothiophene > 3-methyl thiophene and was applied efficiently for ultra-deep adsorptive desulfurization. The 35 ppmwS concentrations of DBT and BT in model oil were decreased down to 2.30 ± 0.20 and 4.28 ± 0.31 ppmwS, respectively, with high selectivity. The reason behind excellent ultradeep desulfurization and high selectivity of S-heterocycles over aromatics is utilization of available unsaturated metal and strong metal-S bonding. In addition, the high mechanical and chemical stability of millimeter-sized composite enabled the easy recyclability with excellent efficiency and high fluidity. All the above excellency shall endow the composite to apply potentially in practical (especially ultra-deep) adsorptive desulfurization process.