Air‐promoted adsorptive desulfurization of diesel fuel over <scp>T</scp>i‐<scp>C</scp>e mixed metal oxides

Abstract

Air‐promoted adsorptive desulfurization (ADS) of commercial diesel fuel over a Ti‐Ce mixed oxide adsorbent in a flow system is investigated in this work. The fresh/spent adsorbents were characterized using X‐ray absorption near edge structure spectroscopy. Results show that sulfoxide species are formed during air‐promoted ADS over Ti 0.9 Ce 0.1 O 2 adsorbent. Adsorption selectivity of various compounds in fuel follows the order of dibenzothiophene sulfone &gt; dibenzothiophene ≃ benzothiophene &gt; 4‐methyldibenzothiophene &gt; 4,6‐dimethyldibenzothiophene &gt; phenanthrene &gt; methylnaphthalene &gt; fluorene &gt; naphthalene. The high adsorption affinity of sulfoxide/sulfone is attributed to stronger Ti‐OSR 2 than Ti‐SR 2 interactions, resulting in significantly enhanced ADS capacity. Adsorption affinity was calculated using ab initio methods. For Ti‐Ce mixed oxides, reduced surface sites lead to O‐vacancy sites for O 2 activation for oxidizing thiophenic species. Low temperature is preferred for air‐promoted ADS, and the Ti‐Ce adsorbent can be regenerated via oxidative air treatment. This study paves a new path of designing regenerable adsorbents. © 2014 American Institute of Chemical Engineers AIChE J , 61: 631–639, 2015