Air‐promoted adsorptive desulfurization of diesel fuel overTi‐Ce mixed metal oxides

Abstract

in Wiley Online Library (wileyonlinelibrary.com) 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 > dibenzothiophene ' benzothiophene > 4-methyldibenzothiophene > 4,6-dimethyldibenzothiophene > phenanthrene > methylnaphthalene > fluorene > 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.

Dynamic catalytic adsorptive desulfurization of real diesel over ultra‐stable and low‐cost silica gel‐supported TiO2

“…Likewise, similar trend of regenerating performance was also found by doping Ce in 15% TiO 2 /C‐SiO 2 ‐2. Interesting, the regeneration temperature required for full recovery of the spent Ce‐doped 15% TiO 2 /C‐SiO 2 ‐2 was 350°C, lower than that of 15% TiO 2 /C‐SiO 2 ‐2 required (400°C), suggesting Ce likely served as a promoter to decompose adsorbed species on the spent adsorbent. The impact of Ce and other promoters on adsorbent regeneration is under investigation and in progress in our lab.…”

“…As a complement to hydrotreating, adsorption desulfurization (ADS) of diesel offers an exciting potential as it enables the removal of the resided trace amount of refractory DBTs that are difficult to be hydrotreated in diesel to proceed in a selective fashion while under ambient temperature and atmospheric pressure, where the adsorbents play the key role . Reported desulfurization adsorbents include π‐complexation sorbent, reduced metal, activated carbon, boron nitride, activated alumina, metal organic frameworks, and so forth.…”

Selective adsorption of thiophenic compounds from fuel over TiO2/SiO2 under UV-irradiation

“…Compared to the three SiO 2 adsorbents, including MCM-41, MCM-48, and A-type SiO 2 , TiO 2 showed much lower uptakes of DBTO 2 , which was attributed to the smaller K (0.0028) and q m (6.76) of TiO 2 for DBTO 2 . While the higher DBTO 2 uptakes of the SiO 2 adsorbents can be ascribed to the dense hydroxyl groups (5-OH/nm 2 on silica materials averagely) [24] present on SiO 2 surface, which adsorb the highly polar DBTO 2 (5.743 D [22]) via hydrogen bonding. Therefore, it can be expected that SiO 2 in 0.3TiO 2 /0.7SiO 2 played a more dominant role on the adsorption of DBTO 2 .…”

“…Diesel desulfurization performance, in particular deep desulfurization performance is determined not only by adsorption capacity of an adsorbent for thiophenic compounds, but also by its adsorption selectivity for these thiophenic compounds relative to other types of fuel components. As clarified in previous communication [19], the adsorbed sulfur species on 0.3TiO 2 /0.7SiO 2 -UV was DBT sulfoxide (similar skeleton as DBTO 2 [22] but not commercially available) rather than the original DBT in fuel, DBTO 2 was chosen as the model sulfur species to study the adsorption selectivity of 0.3TiO 2 /0.7SiO 2 -UV. Table 2 lists the adsorption selectivities (˛) of 0.3TiO 2 /0.7SiO 2 for DBTO 2 , BT, DBT, 4-MDBT and 4,6-DMDBT, and referred Nap from various solvents.…”

Design and synthesis of W-containing mesoporous material with excellent catalytic activity for the oxidation of 4,6-DMDBT in fuels

“…Consequently, desulfurization processes under mild conditions and without hydrogen have been extensively studied. For instance, extractive desulfurization (EDS) [9,10], adsorptive desulfurization (ADS) [11,12], oxidative desulfurization (ODS) [13][14][15][16][17][18] and biological desulfurization (BDS) [19,20]. Among all the processes, ODS is a promising process with high desulfurization efficiency under mild reaction conditions [21][22][23][24].…”