Hydrotreating of Heavy Gas Oil on Mesoporous Mixed Metal Oxides (M–Al2O3, M = TiO2, ZrO2, SnO2) Supported NiMo Catalysts: Influence of Surface Acidity

Oxidative Desulfurization of Tire Pyrolysis Oil over Molybdenum Heteropolyacid Loaded Mesoporous Catalysts

Pyrolysis oil derived from waste tires consists of sulfur content in the range of 7000 to 9000 ppm. For use in diesel engines, its sulfur content must be lowered to 10 to 15 ppm. Though conventional hydrodesulfurization is suitable for the removal of sulfur from tire pyrolysis oil, its high cost provides an avenue for alternative desulfurization technologies to be explored. In this study, oxidative desulfurization (ODS), a low-cost technology, was explored for the desulfurization of tire pyrolysis oil. Two categories of titanium-incorporated mesoporous supports with 20 wt% loaded heteropoly molybdic acid catalyst (HPMo/Ti-Al2O3 and HPMo/Ti-TUD-1) were developed and tested for ODS of tire pyrolysis oil at mild process conditions. Catalysts were characterized by X-ray diffraction, BET-N2 physisorption, and X-ray photoelectron spectroscopy (XPS). The incorporation of Ti into Al2O3 and TUD-1 frameworks was confirmed by XPS. The surface acidity of catalysts was studied by the temperature-programmed desorption of NH3 and pyridine FTIR analyses. HPMo/Ti-Al2O3 and HPMo/Ti-TUD-1 catalysts contained both Lewis and Brønsted acid sites. The presence of titanium in catalysts was found to promote the ODS activity of phosphomolybdic acid. The Ti-TUD-1-supported catalysts performed better than the Ti-Al2O3-supported catalysts for the ODS of tire pyrolysis oil. Hydrogen peroxide and cumene peroxide were found to be better oxidants than tert-butyl hydroperoxide for oxidizing sulfur compounds of tire pyrolysis oil. Process parameter optimization by the design of experiments was conducted with an optimal catalyst along with the catalyst regeneration study. An ANOVA statistical analysis demonstrated that the oxidant/sulfur and catalyst/oil ratios were more significant than the reaction temperature for the ODS of tire pyrolysis oil. It followed the pseudo-first-order kinetics over HPMo/Ti-TUD-1.

Promoting effects of SO42− on a NiMo/γ-Al2O3 hydrodesulfurization catalyst

SO₄²⁻ anchors to a NiMo/γ-Al₂O₃ catalyst, weakening the metal–support interactions, inhibiting MoS₂ aggregation, increasing the number of Ni–Mo–S sites, and thus improving its activity and stability.

A novel single-step hydrogenation of 2-imidazolecarboxaldehyde to 2-methylimidazole over Pd-impregnated Al–Ti mixed oxide and kinetics

A novel and clean route for the hydrogenation of 2-imidazolecarboxaldehyde to 2-methylimidazole with high yield and selectivity over a Pd/ATMO catalyst.

Improvement of Steam Injection Processes Through Nanotechnology: An Approach through in Situ Upgrading and Foam Injection

This study aims to evaluate a high-performance nanocatalyst for upgrading of extra-heavy crude oil recovery and at the same time evaluate the capacity of foams generated with a nanofluid to improve the sweeping efficiency through a continuous steam injection process at reservoir conditions. CeO2±δ nanoparticles functionalized with mass fractions of 0.89% and 1.1% of NiO and PdO, respectively, were employed to assist the technology and achieve the oil upgrading. In addition, silica nanoparticles grafted with a mass fraction of 12% polyethylene glycol were used as an additive to improve the stability of an alpha-olefin sulphonate-based foam. The nanofluid formulation for the in situ upgrading process was carried out through thermogravimetric analysis and measurements of zeta potential during eight days to find the best concentration of nanoparticles and surfactant, respectively. The displacement test was carried out in different stages, including, (i) basic characterization, (ii) steam injection in the absence of nanofluids, (iii) steam injection after soaking with nanofluid for in situ upgrading, (iv) N2 injection, and (v) steam injection after foaming nanofluid. Increase in the oil recovery of 8.8%, 3%, and 5.5% are obtained for the technology assisted by the nanocatalyst-based nanofluid, after the nitrogen injection, and subsequent to the thermal foam injection, respectively. Analytical methods showed that the oil viscosity was reduced 79%, 77%, and 31%, in each case. Regarding the asphaltene content, with the presence of the nanocatalyst, it decreased from 28.7% up to 12.9%. Also, the American Petroleum Institute (API) gravity values increased by up to 47%. It was observed that the crude oil produced after the foam injection was of higher quality than the crude oil without treatment, indicating that the thermal foam leads to a better swept of the porous medium containing upgraded oil.

Insight into the structure and molybdenum species in mesoporous molybdena–alumina catalysts for isobutane dehydrogenation

The relationship of the structure and Mo species of mesoporous molybdena–alumina catalysts with isobutane dehydrogenation has been investigated.

Zirconia (ZrO2) Embedded in Carbon Nanowires via Electrospinning for Efficient Arsenic Removal from Water Combined with DFT Studies

To use zirconia (ZrO2) as an efficient environmental adsorbent, it can be impregnated on a support to improve its physical properties and lower the overall cost. In this study, ZrO2 embedded in carbon nanowires (ZCNs) is fabricated via an electrospinning method to remove arsenic (As) from water. The maximum adsorption capacity values of As(III) and As(V) on the ZCNs are 28.61 and 106.57 mg/g, respectively, at 40 °C. These capacities are considerably higher than those of pure ZrO2 (2.56 and 3.65 mg/g for As(III) and As(V), respectively) created using the same procedure as for the ZCNs. Meanwhile, the adsorption behaviors of As(III) and As(V) on the ZCNs are endothermic and pH dependent and follow the Freundlich isotherm model and pseudo-first-order kinetic model. Both As(III) and As(V) are chemisorbed onto the ZCNs, which is confirmed by a partial density of state (PDOS) analysis and Dubinin-Radushkevich (D-R) model calculations. Furthermore, the ZCNs also possess the capability to enhance or catalyze the oxidation process of As(III) to As(V) using dissolved oxygen. This result is confirmed by a batch experiment, XPS analysis and Mulliken net charge analysis. Density functional theory (DFT) calculations indicate the different configurations of As(III) and As(V) complexes on the tetragonal ZrO2 (t-ZrO2)(111) and monoclinic ZrO2 (m-ZrO2)(111) planes, respectively. The adsorption energy (Ead) of As(V) is higher than that of As(III) on both the t-ZrO2(111) and m-ZrO2 (111) planes (3.38 and 1.90 eV, respectively, for As(V) and 0.37 and 0.12 eV, respectively, for As(III)).

Co-promoted MoO3 nanoclusters for hydrodesulfurization

In this paper, we report the synthesis of ultrasmall Co-promoted MoO₃ nanoclusters (∼2 nm) supported over γ-Al₂O₃ possessing an increased number of Mo edge atoms, using colloidal synthesis for hydrodesulfurization reaction.

Preparation of nano-Ni/meso-Ce–TiO2 by one-step in a sol–gel system and its catalytic performance for hydrogenolysis of xylitol

Nano-Ni/meso-Ce–TiO₂ samples with well-dispersed Ni nanoparticles were prepared by one-step in the AcHE sol–gel system. The Ni and Ce could be directly incorporated into mesoporous TiO₂.