Ultrafast Oxidative Desulfurization of Diesel Fuels by Mass Transfer Enhancement of Polyoxometalate Modified Alumina Catalysts

Abstract

Deep desulfurization of fuels has long been and remains to be a highly challenging issue. In this work, a trilacunary polyoxometalate of Na12[α-P2W15O56]·24H2O (P2W15) was covalently tethered onto the γ-Al2O3 sphere, to which different alkyl chains (C n , n = 8, 12, or 18) were grafted, leading to the formation of the Al2O3-P2W15-C n . When the Al2O3-P2W15-C n were applied to catalyze oxidative desulfurization reaction of dibenzothiophene (DBT) in the presence of H2O2, it displayed high efficiency for removal of sulfur content in 9 min under optimized conditions at 60 °C. In addition, the Al2O3-P2W15-C n exhibited excellent structural stability during the catalytic reaction and can be used to remove 4,6-dimethyldibenzothiophene (4,6-DMDBT) and benzothiophene (BT) from fuel oils. The excellent performance of Al2O3-P2W15-C18 was verified by sulfur removal for an actual diesel sample. Molecular dynamics simulations indicated that DBT showed strong tendency to be adsorbed on active sites, while DBTO2 (dibenzothiophene sulfone) can be desorbed much easier. This work opens up a new avenue for further study on oxidative desulfurization catalytic materials and the influence of catalyst structure on mass transfer.

Design and Synthesis of Amphiphilic Catalyst [C16mim]5VW12O40Br and Its Application in Deep Desulfurization with Superior Cyclability at Room Temperature

“…On the other hand, production of DBTO 2 , a strongly polar substance, involved a weak interaction with IL, which can be desorbed easily from the catalyst surface. In other words, the “polar strategy” of designing the catalyst could not only avoid blocking the active site for the catalyst, but also change the reaction balance to accelerate the reaction …”

“…44 With the increase of alkyl chain length, the absorption intensity of −CH 2 − (2924 cm −1 ) and −CH 3 (2847 cm −1 ) increased accordingly because the vibration greatly changed the dipole moment of the group with the stronger polarity changed. 45 PXRD Spectra. PXRD is an effective characterization technique to determine the crystallinity and structure of solid materials.…”

“…35,52,53 In the W 4f XPS spectra (Figure 3d), two peaks at 37.3 and 35.2 eV were assigned to the W 4f 5/2 and W 4f 7/2 states of W VI , respectively. 45 XPS results further confirmed the successful synthesis of the catalyst and the valence state of [VW 12 O 40 ] 4− was maintained.…”

Oxidative Desulfurization of Liquid Fuels Using Polyoxometalate-Based Catalysts: A Review

“…Liu et al investigated the oxidative removal of sulfur compounds from model fuel using 30 wt % H 2 O 2 as the oxidant and Al 2 O 3 -P 2 W 15 -C 18 as the catalyst. They reported a 100% DBT removal within 9 min at 60 °C.…”

Novel High-Activity Al2O3@ZrXPTA Catalysts and Their Catalytic Oxidative Desulfurization, Mechanism, and Molding

“…In fact, in view of PTA-based heterogeneous catalysts, many researchers have tried to load PTA in large-particle size carriers (such as SiO 2 , − Al 2 O 3 , − activated carbon, , TiO 2 ) to obtain large-particle size composite catalysts, so as to anchor PTA and recycle the catalysts. Among them, Al 2 O 3 has attracted more attention because of its high specific surface area, rich mesoporous structure, high mechanical strength, excellent chemical stability, and low price. − In addition, Al 2 O 3 is rich in many hydroxyl groups, , which can be used as an anchor to firmly anchor the catalyst on the support. Therefore, the γ-Al 2 O 3 with millimeter particle size could be chosen as the support to load the powdery heterogeneous catalysts to obtain a series of large-particle size composite catalysts.…”