Ni/ZnO-based Adsorbents Supported on Al₂O₃, SiO₂, TiO₂, ZrO₂: A Comparison for Desulfurization of Model Gasoline by Reactive Adsorption

Abstract

Reactive adsorption desulfurization (RADS) experiments were conducted over a series of commercial metal oxide supports (Al 2 O 3 -, SiO 2 -, TiO 2 -and ZrO 2 -) supported Ni/ZnO adsorbents. The adsorbents were characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR), and Fourier transform infrared spectroscopy (FTIR) in order to find out the influence of specific types of surface chemistry and structural characteristics on the sulfur adsorptive capacity. The desulfurization performance of all the studied adsorbents decreased in the following order: Ni/ZnO-TiO 2 > Ni/ZnO-ZrO 2 > Ni/ZnO-SiO 2 > Ni/ZnO-Al 2 O 3 . Ni/ZnO-TiO 2 shows the best performance and the three hour sulfur capacity can achieve 12.34 mg S/g adsorbent with a WHSV of 4 h −1. Various characterization techniques suggest that weak interaction between active component and support component, high dispersion of NiO and ZnO, high reducibility and large total Lewis acidity of the adsorbents are important factors in achieving better RADS performance.

Highly stable Ni/ZnO‐Al2O3 adsorbent promoted by TiO2 for reactive adsorption desulfurization

“…This may be attributed to the formation of new acid sites resulting from the structural rearrangement during the hydrothermal treatments. Since the Lewis acid sites are beneficial for the adsorption of thiophene bearing lone pair electrons, 65 the higher concentration of Lewis acid sites in TiO 2 modified sample after three cycles of hydrothermal treatment may be partially responsible for the improved RADS performance as compared to the unmodified one 23 …”

“…The study on the RADS reaction kinetics of Ni/ZnO based adsorbents revealed that the sulfur diffusion in ZnO was identified as the rate‐determining step after partial sulfidation of ZnO, and the high dispersion of ZnO and NiO particles was favorable for the reaction 20‐22 . To enhance the dispersion of Ni and ZnO, different supports have been introduced into the Ni/ZnO‐based catalysts, such as Al 2 O 3 , ZrO 2 , SiO 2 , zeolites 23‐25 . Among the supports being used, Al 2 O 3 is the most common one because of its intrinsic advantages, such as high surface area, low cost and high chemical/mechanical stabilities, triggering extensive interests in the Ni/ZnO‐Al 2 O 3 adsorbents.…”

“…The high‐temperature steaming conditions in the aging process would also promote the formation of the spinel phase 35 . Meng et al 23 found that the presence of ZnAl 2 O 4 could reduce the reducibility and activity of the adsorbents, and the high stability of spinel renders it difficult to be removed once it formed. Moreover, the spinel formation also deteriorated the mechanical strength of the adsorbents 32 .…”

Remarkably high performance of clew-like ZnO superstructure in reactive adsorption desulfurization

“…S4. As can be seen, all samples exhibit a band at 1450 cm -1 attributed to the 19bν (C-C) vibration of pyridine molecules adsorbed at the Lewis acid site [59,60]. Among all tested adsorbents (see Table S3), sample Ni/ZnO-4h possesses the highest concentration of Lewis acid (1.079 mmol g -1 ) compared with other samples, which partially accounts for its high RADS activity.…”

Selective Adsorption of Dimethyl Disulfide on Acid-Treated CuYH@Silicalite-1 Core–Shell Structure: Methyl tert-Butyl Ether as a Competition Component

“…However, during the production process (reaction of isobutene and methanol), the C4 stream (the main source of isobutene) contains many sulfur compounds, such as DMS (dimethyl sulfide) and DMDS (dimethyl disulfide; approximately 45 ppm in MTBE). , The molecular structures of DMDS and MTBE are illustrated in Scheme . Recently, the desulfurization for MTBE is primarily distillation desulfurization, hydrodesulfurization, and adsorption desulfurization. − By comparison, distillation is always accompanied by huge energy consumption, and hydrodesulfurization always requires a harsh operating condition under high temperature and pressure. For deep desulfurization, the adsorption desulfurization has been considered the promising technology due to its mild conditions of atmospheric temperature, low pressure, low energy consumption, and simple operation. , …”