Adsorptive desulfurization of jet fuels over TiO2-CeO2 mixed oxides: Role of surface Ti and Ce cations

A Ti0.9Ce0.1O2 oxide-based adsorbent with high surface area mesopores was studied for adsorptive desulfurization of jet fuel (JP-5: 1055 ppm-w of sulfur) using several techniques, including GC-PFPD, N2 adsorptiondesorption, XRD, XPS and TPD. Ti0.9Ce0.1O2 oxide-based adsorbent effectively adsorbed sulfur and achieved the sulfur reduction of the jet fuel from 1055 ppm-w to lower than 1 ppm-w in multiple cycles of adsorption in a fixed-bed flow system. The spent adsorbent can be regenerated in-situ at the elevated temperature by using air. Some of the sulfur atom in the organic sulfur compounds could be oxidized to form sulfate species by reaction with the surface active oxygen species, while the surface (Ti4+, Ce4+) cations of adsorbent were reduced simultaneously upon adsorption of the sulfur compounds. The formed sulfate species were further removed from the surface during the oxidative regeneration step under an air flow. The deactivation of the adsorbent was potentially caused by sintering and metal cation migration on the surface.