Oxidative Desulfurization of Petroleum Distillate Fractions Using Manganese Dioxide Supported on Magnetic Reduced Graphene Oxide as Catalyst

Vanadium anchored 3D nanoconfined KIT-6 silica walls for fast oxidative desulfurization of fuel: A detailed thermodynamic and kinetic examination

Sulfur contamination in fuel contributes to severe environmental concerns, including acid rain. Conventional desulfurization techniques are often energy-intensive, making oxidative desulfurization (ODS) a promising alternative. However, the efficiency of ODS is hindered by the poor dispersion and stability of metal active sites. In this study, we present a novel, cost-effective, and solvent-free solid-state grinding (SSG) approach for anchoring vanadium nanoparticles (Vn-NPs) into the confined spaces of as-synthesized KIT-6 (AK) for enhanced metal dispersion. Unlike conventional synthesis methodologies, the current approach ensures uniform Vn-NPs dispersion within the AK framework, reduces synthesis steps, and effectively minimizes metal aggregation. A single-step calcination simultaneously facilitates the formation of Vn-NPs within the framework and removes the P123 template. Characterization confirmed the effective Vn-NP dispersion up to 10 wt% without noticeable aggregation, while higher loadings led to particle agglomeration and structural degradation. The optimal V10AK catalyst achieved 97 % DBT conversion in 30 min using 50 mg and an O/S ratio of 4. Kinetic analysis confirmed that the ODS of DBT over V10AK follows pseudo-first-order kinetics, with an activation energy of 37.71 kJ/mol. Thermodynamic parameters (∆H = +35.27 kJ/mol, ∆S = -484.90 J/K) suggest the reaction is endothermic, non-spontaneous, yet feasible under ambient conditions. Additionally, V10AK exhibited remarkable stability and recyclability, making it a promising candidate for real-world ODS applications.

Synergetic Effect of Fe2O3 Doped-CeO2 Nanocomposites Prepared via Different Techniques on Photocatalytic Desulfurization of Heavy Gas Oil

The photocatalytic performances of three Fe2O3–CeO2 nanocomposites were investigated toward the sulfur removal from a petroleum heavy gas oil (HGO) sample. The three composites were prepared by three different routes namely; auto-combustion, post-precipitation and precipitation. The physio-chemical features and optical properties of the presented composites were determined via proper analytical techniques. Formation of Fe2O3–CeO2 solid solution in all the prepared composites was verified via XRD analysis. These composites were then employed in photo-desulfurization of HGO and their activities were investigated at several operating conditions. The highest photocatalytic desulfurization exploit (91.5%) could be detected for the composite which was prepared via auto-combustion technique, denoted as (Fe20Ce80)ac. This maximum percentage of sulfur removal could be obtained under visible light irradiation at the following optimum operating conditions: 15 g/L (as photocatalyst dose), time of 6 h and 2:1 of H2O2 to oil ratio. The subsequent implementation of a solvent extraction step using N-methyl pyrrolidone was needed to attain the deepest desulfurization of HGO. The efficiencies of the presented composites against the process of sulfur removal were discussed in spot of their textural and optical characteristics as well as the available oxygen vacancies through their lattices structures.

Hydrothermal Modification of TS-1 Zeolites with Organic Amines and Salts to Construct Highly Selective Catalysts for Cyclopentene Epoxidation

Developing efficient heterogeneous catalysts for cyclic olefins epoxidation is highly attractive for meeting the growing need for various cyclic epoxides. Herein, hierarchical TS-1 zeolite with relatively abundant mesopores and less amount of surface hydroxyl groups was obtained by hydrothermal modification of an as-synthesized TS-1 zeolite with a mixed solution of ammonia, tetrapropylammonium bromide (TPABr) and KCl. The post-modified TS-1 zeolite exhibited much higher catalytic activity (52% conversion) and epoxide selectivity (98%) for the epoxidation of cyclopentene than the conventional TS-1 zeolites. The excellent catalytic activity of the hierarchical TS-1 could be mainly assigned to the enhancement of the mass transport ability and the accessibility of the active Ti species, while the improvement of epoxidation selectivity may be mainly related to the introduction of a certain amount of K+ that can effectively modulate the coordination environment of Ti species as well as the polarity of the zeolite. This work demonstrated that a highly active and selective catalyst for the H2O2-mediated cyclopentene epoxidation could be obtained by concurrently generating mesopore and extinguishing the unfavorable defective hydroxyl groups through the simple hydrothermal treatment of the conventional TS-1 zeolite with a mixed base/salt solution.

Development of reduced graphene oxide-supported novel hybrid nanomaterials (Bi2WO6@rGO and Cu-WO4@rGO) for green and efficient oxidative desulfurization of model fuel oil for environmental depollution

For the first time, two new kinds of inorganic-organic hybrid nanomaterials (Bi₂WO₆@rGO and Cu-WO₄@rGO) were fabricated by simple hydrothermal treatment and employed for green and efficient oxidative desulfurization of real fuel. The characterization of newly synthesized nanocomposites was performed by SEM, EDX, P-XRD, FT-IR and TGA. SEM and XRD analyses revealed well decoration of dopants (Cu-WO₄ and Bi-WO₃) on the surface of rGO with a crystallite size of <50 nm. The catalytic activity of both nanocatalysts was examined for model (dibenzothiophene) and real fuel (kerosene and diesel) by oxidative desulfurization route. Experimental findings revealed a high efficiency of over 90% under optimal reaction conditions of 0.1 g catalyst, 1 mL of oxidant, and 100 mg/L after 120 min at 30 °C. The major factors affecting desulfurization efficiency (time, temperature, catalyst amount, dibenzothiophene (DBT) concentration and amount of oxidant) and kinetic studies were described. The DBT removal via oxidative desulfurization followed pseudo first-order kinetics with an activation energy of 14.57 and 16.91 kJ/mol for Cu-WO₄@rGO and Bi₂WO₆@rGO, respectively. The prepared catalysts showed promising reusability for the ODS process up to 5 times with no significant decrease in efficiency. In conclusion, the findings confirm the robustness of newly prepared nanocomposite for efficient production of sulfur-free oil.

Deep Adsorption Desulfurization of Fluid Catalytic Cracking Light Gasoline on NiO/ZnO-TiO2 Adsorbents with a High Breakthrough Sulfur Capacity

Two kinds of NiO/ZnO-TiO2 adsorbents were prepared by equal volume impregnation (NiO/ZnO-TiO2-1) and kneading (NiO/ZnO-TiO2-2) methods. The adsorbents were characterized by X-ray diffraction, mercury intrusion porosimetry, scanning electron microscopy, energy dispersive X-ray spectroscopy, H2 temperature-programmed reduction, and H2 temperature-programmed desorption. It was found that NiO/ZnO-TiO2-2 had a smaller average pore diameter and a larger specific surface area as well as a more uniform distribution of the nickel element. Additionally, more Ni0 active sites together with a stronger interaction between the active component and the support were detected on the surface of NiO/ZnO-TiO2-2, which was beneficial to the inhibition of olefin saturation during desulfurization. The desulfurization performance of the adsorbents was investigated in a fixed bed reactor with fluid catalytic cracking light gasoline as a feed oil. The evaluation results confirmed NiO/ZnO-TiO2-2 with a better desulfurization performance with less olefin saturation. It could reduce the total sulfur content from 300 ppmw to less than 5 ppmw, and the breakthrough time and breakthrough sulfur capacity were 91 h and 6.71% (67.1 mg S/g adsorbent), respectively.

Recent Advances in Chitin and Chitosan/Graphene-Based Bio-Nanocomposites for Energetic Applications

Herein, we report recent developments in order to explore chitin and chitosan derivatives for energy-related applications. This review summarizes an introduction to common polysaccharides such as cellulose, chitin or chitosan, and their connection with carbon nanomaterials (CNMs), such as bio-nanocomposites. Furthermore, we present their structural analysis followed by the fabrication of graphene-based nanocomposites. In addition, we demonstrate the role of these chitin- and chitosan-derived nanocomposites for energetic applications, including biosensors, batteries, fuel cells, supercapacitors and solar cell systems. Finally, current limitations and future application perspectives are entailed as well. This study establishes the impact of chitin- and chitosan-generated nanomaterials for potential, unexplored industrial applications.