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In this work, we explored a two-step oxidative desulfurization (ODS) approach using in-situ-generated peroxides in diesel by light irradiation. The supported catalysts were prepared by incipient wetness impregnation and characterized by N 2 adsorption test, X-ray diffraction, and X-ray photoelectron spectroscopy. Kinetic curves for peroxide generation by light irradiation and self-decomposition over a MoO 3 /SiO 2 catalyst were measured. Catalytic activities of the catalysts for ODS were tested. Results showed that (a) the efficiency of peroxide generation in diesel under a mercury lamp was much higher than that under a xenon lamp at the same light intensity and can be enhanced at a higher temperature, (b) with in-situ-generated peroxides in diesel by light irradiation, the ODS conversion of catalysts followed the order of MoO 3 /SiO 2 > V 2 O 5 /SiO 2 > WO 3 /SiO 2 and the conversion reached 75.6% using the MoO 3 /SiO 2 catalyst at the reaction temperature of 45 °C at the O/S ratio of 8, and (c) accompanying the main ODS reaction with hydroperoxides over the MoO 3 /SiO 2 catalyst in diesel, the competing side reaction of peroxide self-decomposition occurred and its kinetics increased dramatically with the reaction temperature. The overall ODS conversion may be affected by the diffusion of bulky refractory sulfur compounds in diesel on the catalyst, which can be enhanced by increasing the pore size of the MoO 3 /SiO 2 catalyst. The two-step oxidative desulfurization approach provides a viable path to achieve clean diesel effectively under mild conditions without using costly hydrogen.

Adsorbent regeneration is critical for a continuous adsorption-regeneration process and often underestimated. In this work, the regeneration of bifunctional Ag X O@SBA-15 for [O]-induced reactive adsorptive desulfurization of liquid fuel is reported and further investigated. The spent Ag X O@SBA-15 was regenerated in various types of solvents followed by calcination and tested in multiple desulfurization-regeneration cycles. The effects of regenerate solvents were also compared systematically. The original and regenerated Ag X O@SBA-15 was characterized by X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, N 2 adsorption, X-ray photoelectron spectroscopy and atomic absorption spectrometry. The recovery of desulfurization capacity using various solvents follows the order of acetonitrile [ acetone [ ethanol [ methanol [ water. Owing to the complete reduction of silver species to Ag 0 and severe agglomeration of Ag 0 , the bifunctional Ag X O@SBA-15 demonstrating [ 85% (2.60 mg-S/g) of sulfur removal dramatically reduced to \ 46% (1.56 mg-S/g) after only 1st-cycle regeneration. It is suggested that polar organic species strongly adsorbed (or residual) on the spent Ag X O@SBA-15, in that case, after solvent wash may contribute to the accelerated decomposition of Ag ? to Ag 0 in the following calcination step. The desulfurization capacity decreased rather mildly in the later regeneration runs. Cautious choice of regeneration conditions and strategies to rational design stabilized adsorbents is required to avert the adsorbent deactivation.