Superior Deep Desulfurization of Real Diesel over MoO₃/Silica Gel as an Efficient Catalyst for Oxidation of Refractory Compounds

Abstract

In this work, deep extractive catalytic oxidative desulfurization (ODS) of hydrotreated real diesel fuel was attained using a synthesized catalyst of supported molybdenum oxide on mesoporous silica gel (MoO3/SG) with a high surface area. The characterization of the catalyst was assessed by Fourier transform infrared, X-ray diffraction, Brunauer–Emmett–Teller, Barrett–Joyner–Halenda, N2 adsorption–desorption, scanning electron microscopy, and energy-dispersive X-ray spectroscopy analysis. The effect of molybdenum loading, M catalyst/V oil, H2O2/sulfur molar ratio, temperature, and reaction duration on the ODS of diesel was examined, aiming to set at the optimum values. Different extraction solvents were evaluated, where acetonitrile was processed with the best performance among all. About 99.9% of sulfur in real diesel was selectively removed using the MoO3 (5 wt %)/SG catalyst under the optimal mild reaction conditions of 45 °C, an O/S molar ratio of 8, an M catalyst/V oil of 0.1 g/mL, and a reaction time of 90 min, employing only one step extraction of ODS products by acetonitrile. Compared to previous research studies on ODS of real diesel, an obviously superior performance was exhibited by the introduced catalyst in this study because of the sufficiently large pore diameter, considerably higher surface area (346.5 m2/g) of the catalyst, good distribution of the active phase on the SG surface, and ODS operating at the optimal conditions. Interestingly, no significant loss in catalyst activity was revealed after recycling seven times in ODS of the dibenzothiophene model; however, the catalyst reusability was relatively limited by the interactions of various hydrocarbons in the real diesel. The studies on overall kinetics and reaction pathway were conducted as well.

Sono-oxidative desulfurization of fuels using heterogeneous and homogeneous catalysts: A comprehensive review

“…Photocatalyst under UV [54] or visible light [55] , nano-sized silica particles including mesoporous silica [56] , aluminum oxide particles [57] , transition metal oxides [58] , activated carbons [59] , modified metal–organic frameworks [60] , Ni catalyst also called sponge metal [61] , nanocomposite [62] , graphene oxide [63] , activated carbon (AC)-supported phosphotungstic acid [64] and fly ash-modified fenton catalysts [65] are used. In the case of using heterogeneous catalysts, the catalytic ODS mechanism [66] , [67] , [68] , [69] , [70] is illustrated in Scheme 1 . DBT, which is transferred from the organic phase to the aqueous bulk phase by ultrasound, diffuses to the outer surface of the solid catalyst by passing across the liquid film (boundary layer) around the supported catalyst particle.…”

An Efficient Co-Based Metal–Organic Framework Nanocrystal (Co-ZIF-67) for Adsorptive Desulfurization of Dibenzothiophene: Impact of the Preparation Approach on Structure Tuning

“…Therefore, researchers have been encouraged to focus on highly efficient methods for reduction of sulfur pollutants in fuels to near-zero levels. Hydrodesulfurization (HDS) is the most common industrial method for desulfurization of liquid fuels; however, the complete removal of thiophenic refractory sulfur compounds such as dibenzothiophene (DBT) and its derivatives requires hard reaction conditions in this process. − So, in the past decades, various alternative techniques including adsorption, , oxidation, − and extraction , were also developed for deep removal of thiophenic compounds under mild conditions. , Among them, adsorptive desulfurization (ADS) is one of the most promising and effective methods. The type and potential of the adsorbent are key factors that dramatically influence the efficiency of this process.…”

Zeolite Stabilized Isolated Molybdenum Species for Catalytic Oxidative Desulfurization

“…随着循环次数的增加, DBT 的氧化脱硫效率 从 99.3%降低至 98.4%, 这微小的下降归因于循环洗涤 过程中导致的催化剂少量损失, 催化剂整体表现出了优 异的稳定性. 而 SiO 2 为载体时, 氧化脱硫效果在 5 次循 环后降低为 58.7%, 这与 Mokhtari [81] 和 Wang [23] [37][38][39][40][41]…”

“…据报道, 高空间位阻的硫化物如 二苯并噻吩更容易通过 ODS 去除 [12][13][14][15][16] . 氧化脱硫反应 中使用的催化剂种类繁多, 比如杂多酸体系 [16] 、金属有 机体系 [17][18] 以及负载型催化剂等 [19][20] , 其中负载型氧化 钼催化剂表现出优异的催化性能 [13,[21][22][23][24] .…”