Enhanced adsorptive-oxidative desulfurization of dibenzothiophene over Ti-MWW using cumene hydroperoxide as oxidant

Ti-containing Mobil composition of matter-twenty-two (Ti-MWW) zeolite was prepared via a two-step post-synthesis process and then characterized by X-ray fluorescence, nitrogen adsorption-desorption isotherms, Fourier transform infrared absorption spectra, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectra. These results indicate that the textural properties of MWW were well preserved after acid treatment and incorporation of titanium. An adsorptive-oxidative desulfurization (AODS) system was successfully developed on the basis of a model oil containing dibenzothiophene (DBT) with the as-prepared Ti-MWW being the catalyst and adsorbent and cumene hydroperoxide (CHP) being the oxidant. The parameters influencing the desulfurization performance were systematically investigated. These parameters include the Ti-MWW dosage, the reaction temperature, the stirring speed, the molar ratio of CHP to DBT and the additions of olefins and aromatics to the system. The conversion rate of DBT reached 99.6% via the catalytic oxidation process and the turnover frequency was 40.1 h(-1). Meanwhile, the oxidation products of DBT were removed by Ti-MWW adsorption. The recycling and regeneration performance of Ti-MWW were also investigated, and the DBT conversion reached 99.5% using the regenerated Ti-MWW. This work provides useful information for the construction of solvent-free oxidative desulfurization systems using a zeolite.

Automated summary

Ti-containing MWW zeolite was prepared and used as a catalyst and adsorbent in an adsorptive-oxidative desulfurization system. The system achieved high conversion rate of DBT and the oxidation products of DBT were removed by Ti-MWW adsorption. The study also investigated the influence of various parameters and the recycling and regeneration performance of Ti-MWW. This work provides valuable information for the construction of solvent-free oxidative desulfurization systems.